1. Field of the Invention
The invention relates to a monitoring module for monitoring a process with an electric arc, with the electric arc being led with a torch, comprising a camera, a photo flash lamp and a control system that controls the photo flash lamp in such a way that it illuminates when the camera records an image and the said components (camera, photo flash lamp, control system) are arranged in a common housing.
2. The Prior Art
For some time now, processes with an electric arc, such as e.g. welding processes, have been monitored in order to be able to recognize failures as early as possible and to interact in a correcting way if necessary. For this purpose, for example, the welding pool is monitored and also the sound emission during the welding process is evaluated in order to be able draw conclusions concerning the quality of the welding process. Some possibilities have already been known from prior art.
The JP 6304754 A for example shows a device for monitoring a welding pool, which consist of a camera and a stroboscope lamp. The lamp is synchronized with the camera in such a way that it emits light when the camera records a picture (a “frame”). The stroboscope illuminates the environment of the welding place in such a way that the latter has approximately the same brightness as the electric arc of the arc welding apparatus.
Another, similar example is the WO 1996/013354 A1, which also discloses a camera for monitoring and a stroboscope lamp for illuminating the melting bath during the welding process.
The EP 1 769 880 A1 shows furthermore an arrangement consisting of a camera and a flash lamp for monitoring the welding point, the camera and the flash lamp of which are arranged at different positions relative to the welding point and are arranged in different angles to the latter in order to avoid the formation of shadows.
Furthermore, the DE 33 33 151 A1 discloses a device and a method, where sound receivers orientated towards a welding or separation point are arranged and the spectrum of the welding sound is continuously analyzed in a control device. This is analyzed with respect to characteristic values important to certain process parameters and feed into the control device of the feed device. In this case, the gas supply, the dosage of the filler material, the feeding of the electrode and/or the positioning of the gun to the workpiece is controlled. The evaluation is complemented by correlation in terms of time and place of the sound measuring or the spectral values concerning the process parameters, such as current, voltage and positioning.
Additionally, the GB 2325107 A shows a device, where a laser projects a first reference mark onto a workpiece to be welded. A video camera records this first reference mark as well as the surrounding of this reference mark and shows a second reference mark into the image. During the welding process, the welding gun is such adjusted, that the first and the second reference mark coincide.
Additionally, the DE 10 2004 039 410 A1 discloses a method and a device for regulating an automated machining process. In this case, by means of a light source and a first optic arranged between the light source and a workpiece to be machined, a line of light is projected onto a region of the workpiece machined by means of a processing head. Furthermore, the line of light is depicted onto a receiving arrangement by a second optic. By means of an evaluation circuit, at least one machining parameter of a machine tool is regulated depending on the comparison of an actual value of a parameter calculated on the basis of the course of profile and a target value.
Furthermore, the U.S. Pat. No. 4,471,207 discloses a system for electric arc welding, where the process can be monitored by means of a sound which is modulated according to the welding voltage and the welding current. The loudness of the sound is changed corresponding to the welding current and the frequency of the sound is changed according to the welding voltage.
Furthermore, the U.S. Pat. No. 4,764,655 shows a laser-materials processing machine, where a focal spot of a laser beam on a workpiece is watched with the help of a video camera. The diameter of the laser beam is calculated on the basis of the recorded image.
Finally, the WO 2007/098609 A1 shows a camera, the housing of which is featured with a compressed air connection. The fed air is thereby used for the cleaning and the cooling. In order to keep clean the lens of the camera, the compressed air is led through an outlet opening arranged in the camera housing in the region of the lens. Thus, an air flow, which leads away from the lens and is adjusted to the optical axis of the camera is created.
Furthermore, the US 2008/0310140 A1 generally shows a diffuser for a flash lamp of a camera.
Furthermore, the WO 98/22850 discloses a filter arrangement for a camera with a frame, a filter inserted into the frame as well as a fixing ring for fixing the filter in the frame.
Finally, the WO 2009/018391 generally discloses a video camera, where the image plane of an image sensor can be rotated with respect to the housing of the camera.
The disadvantage of the known method is that they are proprietary that means designed for the respective type of machine and the respective purpose of application. Additionally, the solutions are comparably expensive and difficult to service due to their low number of units. Also the restricted accessibility, the increased space requirement and the security against the increased impact of dirt of the process such as smoke or splashes that needs improvement are disadvantageous. For this reason, also the maintenance effort increases.